不同尿素、麦麸的添加水平对咖啡渣发酵效果的影响

Effects of different levels of urea and wheat bran on the fermentation effect of coffee grounds

本研究旨在利用微生物发酵的方式处理咖啡渣,提高咖啡渣的营养水平和饲用价值。采用鼠李糖乳酸杆菌、罗伊氏乳酸杆菌、植物乳杆菌、枯草芽孢杆菌和布拉迪酵母菌等为发酵菌种,分别将不同比例的尿素、麦麸添加到咖啡渣中进行28 d的厌氧发酵,检测发酵品质、营养成分、氨态氮和乳酸、乙酸等有机酸含量,评估咖啡渣发酵的效果。结果表明:(1)添加尿素的三个处理组感官评分均显著低于对照组(P<0.05),pH均显著高于对照组(P<0.05),乙酸、氨态氮含量无显著差异(P>0.05),0.5%组和1.0%组的乳酸含量较对照组提高了63.28%和68.97%,1.5%组发酵咖啡渣的尿素氮含量较对照组提高了56.96%(P<0.05);(2)添加不同麦麸处理组的pH均低于对照组(P<0.05),粗灰分含量高于对照组(P<0.05),5%与15%麦麸处理组的蛋白质含量与对照组相比显著提高3.88%和5.99%(P<0.05)。添加1.5%尿素可以显著提高发酵咖啡渣的尿素氮含量,添加麦麸可以改善发酵咖啡渣的发酵品质,其中添加15%麦麸可以显著提高发酵咖啡渣的蛋白质和乳酸含量。

In this study,in order to improve the nutritional value of coffee grounds,a mixture of Lactobacillus rhamnosus,Lactobacillus reuteri,and Lactobacillus plantarum,Bacillus subtilis and Saccharomyces bradyi was used for coffee grounds fermentation.Different levels of urea and wheat bran were added to coffee grounds as nutrients supplementation.After 28 days of anaerobic fermentation,the fermentation quality,nutrient composition,ammonia nitrogen,lactic acid,acetic acid and other organic acids were detected to evaluate the result of coffee residue fermentation.The results showed that:(1)The sensory scores of the three treatment groups added urea were significantly lower than those of the control group(P<0.05);pH was significantly higher than that of the control group(P<0.05),and there was no significant difference in the content of acetic acid and ammonia nitrogen(P>0.05);The lactic acid content of 0.5%and 1.0%groups increased by 63.28%and 68.97%compared with the control group,and the addition of 1.5%urea significantly increased the urea nitrogen content of fermented coffee groups by 56.96%;(2)The pH of the treatment group with different wheat bran was lower than that of the control group(P<0.05),and the crude ash content was higher than that of the control group(P<0.05);Compared with the control group,the protein content of the 5%and 15%wheat bran treatment groups increased significantly by 3.88%and 5.99%.Adding 1.5%urea could significantly increase the urea nitrogen content of fermented coffee grounds.The addition of wheat bran could improve the fermentation quality of fermented coffee groups,and 15%of wheat bran could significantly increase the content of protein and lactic acid.